The present invention relates generally to the packaging of crabmeat and specifically to a method for packaging crabmeat in flexible airtight containers. This method will allow packaging a successful marketable product while at the same time helping in slowing down spoilage and avoiding the undetected growth of anaerobic bacteria.
Traditionally, crabmeat products packaged in flexible airtight containers have been sterilized or frozen. Based on this invention, crabmeat will be packaged in flexible airtight containers, pasteurized, and offered to the consumer in a refrigerated state, rather than in a shelf stable, sterilized container or a frozen state. As is explained further in this text, sterilization or freezing alter the texture, taste, and in general, the fresh characteristics of the crabmeat.
Crabs are caught in the seawaters by fishermen and brought alive to the landing sites. Live crabs are then steam cooked or boiled in order to facilitate the picking process, which consists of the separation of the meat from the shell and other body parts. Cooked crabs are then ventilated to cool them and bring the temperature down to as close to ambient temperature before putting them in a temporary cooler or transferring them immediately to the picking room. In the picking room the crabs are cleaned and the different meats are picked. The meats may include jumbo lump, comprising the meat of the swimming legs, lump, comprising the muscle of the walking legs and big pieces of body meat, special, comprising the remaining body meat, most of which is shredded, claw, comprising dark meat from the claws, and cocktail claw, comprising meat from the claw attached to the moveable jaw of the claw. There are other varieties of these mentioned meat types including imperial, which is very large jumbo lump from bigger than normal crabs, super lump, which is only larger pieces of lump meat, and backfin, which is a mixture of lump and special meat pieces.
Once the different meats are picked, they are sorted by meat type and finally cleaned to remove any residual shell pieces that may have been attached to the meat and any other matter from the body or claws of the crab that are not intended for the consumer. The sorted and cleaned crabmeat is then packed, usually by hand, into the desired containers for packaging and pasteurization. Sealed containers waiting to be pasteurized are generally placed on ice or in ice water to maintain the holding meat cold and avoid excessive reproduction of bacteria that could render the pasteurization insufficient. Typical packaging vessels include metal cans, plastic cups, and flexible pouches. Once the containers are pasteurized, they are then placed in storage and packed for transportation and distribution to the customers.
In an atmospherically sealed metal can, the amount of air is quite abundant and therefore the danger of undetected anaerobic bacterial degradation is very unlikely. Typically one pound of crabmeat is packaged in a metal can with dimensions 401×301 or 4 1/16 inch diameter by 3 1/16 inch tall. This can has a volume capacity of about 650 ml. Assuming, in an effort to simplify, that crabmeat has a specific weight of 1, then one pound of crabmeat occupies 454 ml, the volume of free air left in the can is then 196 ml. Therefore, the air to meat ratio in the can is quite comfortable, such as about 43%.
Plastic airtight containers are also used to pack pasteurized crabmeat, similarly to metal cans. Except they may present several additional problems encountered during the pasteurization step of the packaging process. Common in the industry is the use of a plastic cup with an aluminum easy open lid. The volumetric capacity of a one pound plastic cup is about 515 ml. Simplifying again and assuming that one pound of crabmeat occupies 454 ml we end up with only 61 ml of free air or a air to meat ratio of a little over 13%. The plastic cups inflate more during the heating cycle of pasteurization because they are less rigid than metal. The plastic to aluminum seal is not as strong as the metal-to-metal seal of the traditional metal can and air can escape through micro pores in the seam during the pasteurization process. As the pasteurized plastic containers are transferred to the cooling cycle, micro pores close and the lost volume of air is not replaced. When the containers finally reach the storage temperature, the containers end up with an internal negative pressure due to the lost volume of air and the walls of the plastic containers are drawn inward. The misshapen containers cannot be sold to consumers, and therefore valuable product is lost. Plastic containers used according to the method of the present invention, however, have a controlled volume of air and a lower initial pressure going into the heating cycle of pasteurization. Therefore, it is less likely for air to escape during the pressure increase of the heating process. If air does not escape during the heating process, decrease in pressure will not occur within the can as the can cools and therefore, the shape of the can will be maintained.
The risk with properly pasteurized products is temperature abuse. Temperature abuse occurs when the crabmeat product is taken out of refrigeration, whether at the kitchen, when purchased by a consumer, or during the shipping process, and is allowed to remain at temperatures favorable to the reproduction of bacteria to the level that would make the product unsafe for human consumption. Bacteria that survive pasteurization will reproduce and spores will hatch. With extended temperature abuse, the product will eventually spoil and because of the foul odor created by such spoilage it will serve as a warning to the consumer of the damage to the product. Spoilage bacteria require an aerobic atmosphere to reproduce and hatch. It would seem simple to avoid spoilage to just pack the crabmeat in an anaerobic atmosphere, like a vacuum. Unfortunately, however, bacteria also exist that reproduce in an anaerobic atmosphere.
One of the most troublesome anaerobic bacteria in the crabmeat industry is Clostridium botulinum. The toxins of C. botulinum can cause consumer illness (e.g., botulism) as well as death. The pasteurization process destroys most of the C. botulinum organisms, but its spores are much more difficult to destroy. Even though its presence in crabmeat is very unlikely, the potential exists and is thus addressed by the present invention.